Means and method for gluing waterproof blanks



Sept 23 1941 s. BERG-STEIN v 2,256,888

MEANS AND METHOD FOR GLUING WATERPROOF BLANKS Filed Jan. 29, 1940 ATTORNEYS.

Patented Sept. 23, 19241 MEAN S AND RIETHOD FOR GLUING WATERPROOF BLANES Samuel Bergstein, Cincinnati, Ohio Application January 29, 1940, Serial No. 316,188

9 Claims. I (Cl. 93-36) In gluingordinary cartons, such as butter cartons for example, which have waxed or otherwise waterproofed surfaces, it is well known to apply heat along the` seams to be glued, which removes the wax so that the adhesive will adherel between the seam portions when they are folded into overlapped relation. That is, it is well known to mel* or scrape. the paraftlne on the glue or sealing flap on that side of one of its surfaces which is to be attached or adhesively secured to th opposite wall, and to likewise melt or scrape off the in'ner portion adjacent the edge of the opposite wall to which the sealing edge is to be attached. This can readily be done because of the fact that the melting or scraping is done on continuous longitudinal lines, to form the lengthwise seam of the carton, and thusremoving by heating or scraping the outer surface of the carton is not marred.` My invention relates to bringing about adhesion at the four corners of a knock-down box, formed from a waxed coated or otherwise waterproofed blank, which introduces new and difficult problems which cannot be successfully accomplished by the prior practice outlined above. Most of the more successful types of glued corner knock-down boxes involve the securing of a portion of theinnr surface or a portion of the outer surface of the blank, at each of four corners. To carry this out on a blank whichhas been waterproofed on both surfaces, and so is repellent to adhesive, involves then the in Figure 3 in erect form, after the sides have been lifted.

Figure 5 is a diagrammatlcal illustration of a portion ofv a machine for carrying out my invention.

Figure 5a is a continuation of Figure 5.

Figure 6 is an enlarged fragmentary'plan view taken along line 6 4 of Figure 5.

The blank shown in Figure 1 comprises a main body panel III, end walls II and I2, having ar- .ticulatedthereto corner flaps I3, I4, I5 and I8,

and side walls I1 and Il. There are angular lines of fold 20 in the side walls, defining triangular portions thereof, 2I, 22, 23 and 2l. The

terms end walls and .side walls` are used herein for purposes of clarity 'in description, and without reference to the relative dimensions of the walls. The surfaces of this blank have been waterproofed by a coating of wax, by immerslng it in a bath of molten parafflne, or running it be- -tween two rolls carrying molten parafline on the surfaces, or by other well known means, which form no part of this present invention.

pre-treating by heat or otherwise of four distinct pairs of meeting surfaces, a't the four respective corners, a total of eight separate surface portions. Since these surface portions are separated from each other =by the walls ol the blank, and since they are on opposite sides of the blanky itself, the problems involved in removing thewax or coating from these portions is readily apparent, and furthermore this must be accomplished without defacing or disrupting the coating on the intervening portions of the blank. between the areas which are to be joined together. The accomplishment of the foregoing is one of the objects of my invention, and additional objects will become apparent as the description proceeds.

Referring now to the drawing: Figure 1 shows my preferred type of flat blank. Figure'2 shows one step in the folding of the blank shown in Figure 1.

Figure 3 illustrates the blank shown in Figure 1 glued and-folded in knock-down form, in which condition itis shipped to the user.

Figure 4 illustrates the knock-down. box shown Figure 2 shows a step in the folding of the blank shown invFigure 1.v As illustrated,.the side walls I1 and I8 have been folded inwardly to overlie the main body panel, the triangular portions 2|, 22, 23 and 24 thereof having been folded reversely or backwardly to lie facing upwardly thereon. Also the corner aps I3, I4, I5 and I6, have been folded inwardly to overlie the end walls II and I2, to which said corner flaps are articulated. v

Referring now to Figure 5,- the blank in the folded position shown in Figure 2 enters the machine from .the direction indicated by-` the arrow. AMy device as shown in Figure 5 may either be incorporated into a machine for folding the boxes in this manner, or can be used as a successive continuous step after another machine unit has delivered the blank in the folded position then shown to my machine. The folding to bring the blank to the form as shown in Figure 2 may be carried out, as for example, as shown in my U. S. Patent No.'1,926,364. After leaving the first section of the machine as illustrated in Figure 2 of the aforesaid patent, and changing its position in relation to its direction of travel, the folded blank is in the condition illustrated in Figure 2 of this case, and is travelling in the direction of. motion indicated by the arrow X of Figure 5 or Y of Figure 2 of. this case. This is merely cited.

form a part of the presentf invention.

useof these spaced overhead heated members it can be seen. that the paraine can be softened or removed, from the desired meeting surfaces of the corner portions only, thereafter in the further course of travel adhesive is applied between the meeting surfaces of these corners, for example by the overhead glue wheels indicated at 32, thereafter in the course of further travel by the use of twist belts 34 and the swords 35, the end walls are folded inwardly so that the infolded corner flaps overlie the reversely folded triangular portions, and the boxes thereafter are brought between pressure belts indicated at 36 to secure adhesion.

' In Figure 3 is shown a waterproofed glued corner infolded knock-down box as produced by the process above described, in its flat knock-down form ready for shipment. Figure 4 illustrates this same knock-down box after it has been erected by the user, which is done merely by r-aising the sides, in which form it is now prepared for the introduction of its contents.

Among the features of my invention which should be particularly noted'are the following:

The blanks are pre-folded in such a manner that the surfaces to be joined together, that is the area at the edge of the walls as well as the sealing flaps, are folded to face upwardly and after they have been thus -folded they pass under heating elements which are so arranged that they contact only the surface areas to be joined together. Because these surface areas are doubled, that is they are folded portions which are higher by at least a thickness of the board itself than the remaining blank area, the heated elements do not contact the intermediate wall portions of the blank as the blank passes beneath them. In other words, successive folding operations have been carried out on the blank until the blank is in folded position wherein the' side walls are folded inwardly and triangular corner portions are fclded back to lie -upon the side walls, upwardly facing, and the corner flaps are also folded in to lie on top the respective walls to which the flaps are 4articulated land in this folded position the blank is carried under spaced heating means which direct heat upon the reversely folded triangular portions and the infolded corner flaps.

In the particular device which I have constructed overhead electric strip-heating units are shown; which serve the dual purpose of heating the areas just described and also of retaining these corner flaps and triangular flap portions in folded condition; that is, the heating units themselves act as overhead hold-down members to retain the folds in `folded position. If it is desired, it is apparent that I might use timed overhead moving heating members, to contact these por` tions, but in practice I have not found this to be necessary as the stationary heaters described do the work satisfactorily and are more simple than moving members would be.

Regardless lof the particular form which the heating members may take, however, an important point is that through the use of heated members at the particular stage of folding where both meeting surfaces of the corner flaps to be joined are facing upwardly, I have achieved heat treatment of these particular areas without disrupting or defacing the coating on other walls or panel portions. That is, because the corner portions to be joined are overlying the main panel and other walls .of the blank so they are vin effect separated from the main panel and other walls by -lying in a plane above them. I am enabled to treat the specific portions or walls so folded without 'affecting other blank portions which lie therebetween.

By reference to treated; or coated, or waterproofed blanks herein, I intend to cover any blank made of paperboard or the like which has been treated either on one or both surfaces by paraiiine or wax or anyv similar material which is normally adhesive-repellent, and which is also heat-softenable. It is obvious that my invention can be applied to other types of folded knockdown boxes other than the one used here for illustrative purposes, so long as the principles I have disclosed are employed. Also it is obvious that while I dealt in the description herein with a tray or half of a telescope box, that the blank might readily have a lid hinged to one of the side walls, to make a one piece type of box, and all such variations are contemplated within the e scope of my invention.

Prior practice previously referred to involves the procedure of wax removal from a flat blank, followed by.the folding operation. My present concept as disclosed involves a preliminary prefolding operation, followed by wax removal from said pre-folded areas while retained in pre-folded condition, and thereafter a subsequent folding to bring said pre-folded, wax-free areas into a superposed position.

Having thus described my invention, what I claim as new and novel and desire to secure by Letters Patent, is:

1. In a machine for making knock-down boxes from blanks having waterproofed surfaces, means for heat treating localized cornerareas, including means to move said blanks along, means to fold meeting surfaces of each corner portion into upwardly facing position, stationary, overhead hold-down meansto retain said folded portions in folded position, and means to heat said hold-down means.

2. In a machine for making knock-down boxes from blanks having waterproofed surfaces, means for heat treating localized corner areas, including means to move said blanks along, means lto fold meeting surfaces of each corner portion into upwardly facing position, stationary, overhead'means to retain said meeting surfaces in foldably tensioned position, means to apply heat to said surfaces, and means for thereafter further folding said blank to bring said meeting surfaces into contacting position, adhesive having been applied therebetween.

3.','I'he method of pre-treating by heat four pairs of meeting surfaces of corner areas .of blanks having waxed surfaces which comprises moving said blanks, folding said blanks to bring said pairs of meeting surfaces of corner areas into upwardly facing position overlying other blank portions, and applying heat. to the folded portions from above to remove the wax from said surfaces without impairing the waxed surfaces of underlying blank portions.

4. In a machine for heat-treating alternate blank areas of waxed blanks, means for moving said blanks and bringing same into folded position wherein meeting surfaces of corner portions lie facing upwardly and thereafter in the course of further motion, moving said blanks under fixed overhead heated members which membersretain the folded position of said upwardly facing portions and contact said portions of folded reversely to lie upwardly facing there-A on, and the end walls are folded outwardly facing thereon, overhead heated means for contacting said upwardly facing triangular portions and corner flaps, said means acting to retain all folded portions in foldably tensioned position, and means for thereafter folding in said end walls, adhesive having been applied between meeting surfaces of said triangular portions and said corner flaps.

6. Ina machine for making boxesfrom blanks having a wax-like surface, means for moving along a blank with portions thereof in folded position so as to overlie other portions, in combination with spaced. overhead hold-down means for retaining said portions non-frictionally, and means for removing said wax-like surface from said pre-folded portions only'comprising means to heat said hold-down means.

'7. A method of gluing waxed blanks which includes folding portions of said blanks, substantially removing the wax from said pre-folded portions by moving said blanks beneath fixed. heated means against which said folded portions have resilient contact, and thereafter additionally folding said blanks to bring said folded, waxfree portions into contact, adhesive having been applied therebetween.

s. A method or gluing waxed bunks which 111-' cludes pre-folding portions of said blank to bring opposite surfaces of the blank into upward facing position overlying other portions of the blank. substantially removing the wax from said pre-folded upwardly facing portions by causing them to contact heated members by the resilience of the folded portions, the vvarious blank portions being essentially out of contact with each other, and thereafter additionally folding said blank to bring said pre-folded wax-free portions into superposed position.

9. A method of making knock-down boxes from blanks lhaving pre-waterproofed surfaces, which blanks require the preparation of waterproofed areas on both sides of the blank for the v bonding by means of adhesive, comprising moving the blanks along, folding said blanks so as to present all such areas upon one side of the blanks in folded portions overlying other portions of the blanks, moving the blanks beneath stationary hold-down means which retain said folded portions as said blanks move, and heating at least a portion of said hold-down means SAMUEL BERGSTEIN. 

